The present inventions are generally related to providing adequate wheelchair securement in large accessible transport vehicles (referred to herein as “LATVs”). LATVs are transport vehicles which are designed for use by both seated and standing passengers. The Americans with Disabilities Act (ADA) mandates that all public transit service providers must accommodate persons with disabilities, including those who must use a wheelchair as their seat in the transport vehicle. ADA also mandates that, for the safety of the wheelchair user and near-by passengers, the wheelchair must be secured so that it will not move more than 2″ in any direction during normal vehicle operation. In addition, four tiedown straps must be attached to the wheelchair—two in front and two in the rear—that are sufficiently strong to withstand a crash event that could generate total forces as high as 4000-5000 lbs on the rear tiedowns. Occupant restraint belts must also be made available in the wheelchair stations, but there is no requirement that they be used.
Although securement straps that meet these requirements are the norm in today's LATVs in the US, a number of pressing problems remain with the prior art four-point strap-type securement technology. For example, the prior art devices are difficult to apply, especially on the wall side of the vehicle. Also, the LATV operator (“operator”) must leave the driver's station to attach the prior art devices, which not only significantly increases the dwell times at stops but also requires the operator to encroach into the wheelchair person's personal space. As a result, the prior art devices are often misapplied, or worst still, are not used at all. Most importantly, the prior art securement approach also means that wheelchair passengers do not have independent access to public transportation equal to that of all other passengers.
In Europe and Canada, rear-facing wheelchair passenger stations (referred to herein as “RF-WPSs”) are quickly becoming accepted and, in Europe, RF-WPSs are now the norm for LATVs. The RF-WPSs are passive in that the RF-WPSs do not physically connect the wheelchair to the vehicle, and instead rely upon various barriers to control wheelchair movement. Typically, the barriers located within a RF-WPS include a rear-facing padded bulkhead (also termed forward excursion barrier (“FEB”) against which the wheelchair is backed. The FEB is intended to prevent forward movement of the wheelchair in the vehicle when it is braking. On the aisle-side of the WPS there is often a floor-to ceiling stanchion (steel tube) barrier, that is intended to prevent rotation or tipping of the wheelchair towards the aisle (laterally) during vehicle turns. Some installations do not include a lateral barrier (stanchion), therefore placing the wheelchair at high risk of tipping or swerving into the aisle.
The prior art RF-WPSs are not designed to handle crash magnitude forces and instead are only concerned with forces which are expected to be generated during emergency driving events, such as maximum braking or swerving. This approach assumes that, because of the relative safety of LATVs used in fixed route service, it is highly unlikely that LATVs carrying wheelchair users will be in a vehicle collision. Based upon research studies involving emergency driving of LATVs, the maximum deceleration force which may be encountered during emergency driving events is believed to be less than 1 g.
The RF-WPS concept has the potential of resolving many of the problems of the prior art four-point strap-type devices, in that the wheelchair user gains independent use of public transportation, the operator can remain in the drivers station, and bus stop dwell times are reduced. However, there are still several problems with the prior art RF-WPSs. For example, it is understood that the prior art RF-WPSs allow wheelchairs to move in excess of 2″ during severe driving conditions, which may cause some types of wheelchairs to tip or swing into the aisle. As a result, auxiliary securement straps attached by drivers are required to prevent such tipping, which nullifies one of the main goals and advantages of the RF-WPS concept—user independence. Also, prior art devices do not allow a close proximity fit between the wheelchair occupant and the FEB, which increases the injury risk in the event of panic breaking or a frontal collision. Finally, prior art lateral barrier installations often protrude into the center bus aisle creating passenger flow problems, as well as maneuvering problems for a second wheelchair passenger.